An Assessment of Anthropogenic Impact in a Nature Reserve: the Santoña Marshes (Northern Spain)

The Santona Marshes Nature Reserve is one of the most important ecosystems of the Spanish Cantabrian coast due to its ecological value as a wintering area for migratory birds. Since an increase in population and substantial changes in the use of land have been observed in this area during the last century, the aim of this work was to attempt to see if anthropogenic activities are recorded in the accumulating sediments. Two sediment cores (50 cm length) were collected for isotopic dating (210Pb and 137Cs) and geochemical study (heavy metals). The data indicate an increasing trend in sedimentation rates during the last century, probably related to the progressive loss of the estuarine domains and the changes in their original hydrodynamic conditions due to infilling and the construction of dykes. However, no significant anthropogenic inputs of heavy metals have been detected in recent times.